Drupal! Its my favorite CMS and the only one that I use on the sites I setup. Chadarius.com is a Drupal site. In fact I'm so lazy with themes that I still haven't really changed the default drupal theme here since I upgraded to 5.3 over a year ago. One of these days I'll get around to it!

Chicago has its own great Drupal user group at http://cdmug.org. Those guys are putting on http://drupalcampchicago.org.